I have to wear glasses all the time now (contacts don't work for me because of dry eye) and I've been using
transition glasses for about five years now. When photochromic lens were first introduced, they sucked and were always partially tinted. Now they work so well that I don't have to deal with:
~ lost clip-ons
~ unavailable alternate pairs of glasses
~ having the wrong glasses on
The only down side is that I still need clip-ons in the car because the wind shield has UV protection so the auto tinting does work there. So I keep a pair of clip-ons behind my visor to grab at a moment's notice. I doesn't hurt that I live in the cloudy northwest too. 8-)